cppenv.texi revision 102780
1@c Copyright (c) 1999, 2000, 2001, 2002 2@c Free Software Foundation, Inc. 3@c This is part of the CPP and GCC manuals. 4@c For copying conditions, see the file gcc.texi. 5 6@c --------------------------------------------------------------------- 7@c Environment variables affecting the preprocessor 8@c --------------------------------------------------------------------- 9 10@c If this file is included with the flag ``cppmanual'' set, it is 11@c formatted for inclusion in the CPP manual; otherwise the main GCC manual. 12 13@ftable @env 14@item CPATH 15@itemx C_INCLUDE_PATH 16@itemx CPLUS_INCLUDE_PATH 17@itemx OBJC_INCLUDE_PATH 18@c Commented out until ObjC++ is part of GCC: 19@c @itemx OBJCPLUS_INCLUDE_PATH 20Each variable's value is a list of directories separated by a special 21character, much like @env{PATH}, in which to look for header files. 22The special character, @code{PATH_SEPARATOR}, is target-dependent and 23determined at GCC build time. For Windows-based targets it is a 24semicolon, and for almost all other targets it is a colon. 25 26@env{CPATH} specifies a list of directories to be searched as if 27specified with @option{-I}, but after any paths given with @option{-I} 28options on the command line. The environment variable is used 29regardless of which language is being preprocessed. 30 31The remaining environment variables apply only when preprocessing the 32particular language indicated. Each specifies a list of directories 33to be searched as if specified with @option{-isystem}, but after any 34paths given with @option{-isystem} options on the command line. 35 36@ifset cppmanual 37See also @ref{Search Path}. 38@end ifset 39 40@item DEPENDENCIES_OUTPUT 41@anchor{DEPENDENCIES_OUTPUT} 42@cindex dependencies for make as output 43If this variable is set, its value specifies how to output 44dependencies for Make based on the non-system header files processed 45by the compiler. System header files are ignored in the dependency 46output. 47 48The value of @env{DEPENDENCIES_OUTPUT} can be just a file name, in 49which case the Make rules are written to that file, guessing the target 50name from the source file name. Or the value can have the form 51@samp{@var{file} @var{target}}, in which case the rules are written to 52file @var{file} using @var{target} as the target name. 53 54In other words, this environment variable is equivalent to combining 55the options @option{-MM} and @option{-MF} 56@ifset cppmanual 57(@pxref{Invocation}), 58@end ifset 59@ifclear cppmanual 60(@pxref{Preprocessor Options}), 61@end ifclear 62with an optional @option{-MT} switch too. 63 64@item SUNPRO_DEPENDENCIES 65@cindex dependencies for make as output 66This variable is the same as the environment variable 67@env{DEPENDENCIES_OUTPUT} (@pxref{DEPENDENCIES_OUTPUT}), except that 68system header files are not ignored, so it implies @option{-M} rather 69than @option{-MM}. However, the dependence on the main input file is 70omitted. 71@ifset cppmanual 72@xref{Invocation}. 73@end ifset 74@ifclear cppmanual 75@xref{Preprocessor Options}. 76@end ifclear 77@end ftable 78